/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.google.android.apps.iosched.io;

import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT;
import static org.xmlpull.v1.XmlPullParser.END_TAG;
import static org.xmlpull.v1.XmlPullParser.START_TAG;
import static org.xmlpull.v1.XmlPullParser.TEXT;

import de.google.android.apps.iosched.provider.ScheduleContract;
import de.google.android.apps.iosched.provider.ScheduleContract.Rooms;
import de.google.android.apps.iosched.provider.ScheduleContract.Sessions;
import de.google.android.apps.iosched.provider.ScheduleContract.Tracks;
import de.google.android.apps.iosched.provider.ScheduleDatabase.SessionsTracks;
import de.google.android.apps.iosched.util.Lists;
import de.google.android.apps.iosched.util.ParserUtils;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.content.ContentProviderOperation;
import android.content.ContentResolver;
import android.database.Cursor;
import android.net.Uri;

import java.io.IOException;
import java.util.ArrayList;

public class LocalSessionsHandler extends XmlHandler
{
	public LocalSessionsHandler()
	{
		super(ScheduleContract.CONTENT_AUTHORITY);
	}

	@Override
	public ArrayList<ContentProviderOperation> parse(XmlPullParser parser, ContentResolver resolver)
			throws XmlPullParserException, IOException
	{
		final ArrayList<ContentProviderOperation> batch = Lists.newArrayList();

		int type;
		
		while ((type = parser.next()) != END_DOCUMENT)
		{
			if (type == START_TAG && Tags.SESSION.equals(parser.getName()))
			{
				parseSession(parser, batch, resolver);
			}
		}

		return batch;
	}

	private static void parseSession(XmlPullParser parser, ArrayList<ContentProviderOperation> batch,
			ContentResolver resolver) throws XmlPullParserException, IOException
	{
		final int depth = parser.getDepth();
		
		ContentProviderOperation.Builder builder = ContentProviderOperation.newInsert(Sessions.CONTENT_URI);
		builder.withValue(Sessions.UPDATED, 0);
		
		long startTime = -1;
		long endTime = -1;
		String title = null;
		String sessionId = null;
		String trackId = null;
		String tag = null;
		int type;
		
		while (((type = parser.next()) != END_TAG || parser.getDepth() > depth) && type != END_DOCUMENT)
		{
			if (type == START_TAG)
			{
				tag = parser.getName();
			}
			else if (type == END_TAG)
			{
				tag = null;
			}
			else if (type == TEXT)
			{
				final String text = parser.getText();
				
				if (Tags.START.equals(tag))
				{
					startTime = ParserUtils.parseTime(text);
				}
				else if (Tags.END.equals(tag))
				{
					endTime = ParserUtils.parseTime(text);
				}
				else if (Tags.ROOM.equals(tag))
				{
					final String roomId = Rooms.generateRoomId(text);
					
					builder.withValue(Sessions.ROOM_ID, roomId);
				}
				else if (Tags.TRACK.equals(tag))
				{
					trackId = Tracks.generateTrackId(text);
				}
				else if (Tags.ID.equals(tag))
				{
					sessionId = text;
				}
				else if (Tags.TITLE.equals(tag))
				{
					title = text;
				}
				else if (Tags.ABSTRACT.equals(tag))
				{
					builder.withValue(Sessions.ABSTRACT, text);
				}
			}
		}

		if (sessionId == null)
		{
			sessionId = Sessions.generateSessionId(title);
		}

		builder.withValue(Sessions.SESSION_ID, sessionId);
		builder.withValue(Sessions.TITLE, title);
		// Use empty strings to make sure SQLite search trigger has valid data
		// for updating search index.
		builder.withValue(Sessions.ABSTRACT, "");
		builder.withValue(Sessions.REQUIREMENTS, "");
		builder.withValue(Sessions.KEYWORDS, "");

		final String blockId = ParserUtils.findBlock(title, startTime, endTime);
		
		builder.withValue(Sessions.BLOCK_ID, blockId);

		// Propagate any existing starred value
		final Uri sessionUri = Sessions.buildSessionUri(sessionId);
		final int starred = querySessionStarred(sessionUri, resolver);
		
		if (starred != -1)
		{
			builder.withValue(Sessions.STARRED, starred);
		}

		batch.add(builder.build());

		if (trackId != null)
		{
			final Uri sessionTracks = Sessions.buildTracksDirUri(sessionId);
			
			batch.add(ContentProviderOperation.newInsert(sessionTracks).withValue(SessionsTracks.SESSION_ID, sessionId)
					.withValue(SessionsTracks.TRACK_ID, trackId).build());
		}
	}

	public static int querySessionStarred(Uri uri, ContentResolver resolver)
	{
		final String[] projection =
		{ Sessions.STARRED };
		final Cursor cursor = resolver.query(uri, projection, null, null, null);
		
		try
		{
			if (cursor.moveToFirst())
			{
				return cursor.getInt(0);
			}
			else
			{
				return -1;
			}
		}
		finally
		{
			cursor.close();
		}
	}

	interface Tags
	{
		String SESSION = "session";
		String ID = "id";
		String START = "start";
		String END = "end";
		String ROOM = "room";
		String TRACK = "track";
		String TITLE = "title";
		String ABSTRACT = "abstract";
	}
}
